1. Field of the Invention
This invention relates to an apparatus for cleaning the reverse surface of a semiconductor wafer opposite to the major surface thereof, and more particularly to a cleaning apparatus suitable for use in combination of a resist coating apparatus.
2. Description of the Related Art
In the process of manufacturing a semiconductor device, in general, a predetermined pattern is printed on a substrate such as a semiconductor wafer or an LCD glass substrate by the use of photolithography. For this end, a resist coating apparatus for coating a substrate with a resist, an exposure apparatus for exposing the coated substrate, a development apparatus for developing the exposed resist, etc. are used. In the treatment process using these apparatuses, contaminants such as particles, etc. must be eliminated almost completely in order to enhance the yield of products. Particles with a diameter of as small as about 1 .mu.m, if they are attached on the reverse surface of a substrate, may cause a focus error at the time of exposure since they raise the substrate only slightly. Such adhesion of particles can occur whenever the substrate is transferred from one of the treatment apparatuses to another. Therefore, cleaning of the reverse surface of a substrate is performed by means of a cleaning apparatus to eliminate the particles.
A cleaning apparatus is generally known, which performs a treatment of brushing the reverse surface of a semiconductor wafer by means of a brush while rotating it with the major surface thereof held by vacuum attraction of a spin chuck. The brush is rotatably held by a tip end of an arm swingably provided on a side portion of the spin chuck. The reverse surface of a wafer is cleaned by applying cleaning water thereto while spinning the brush thereon, and thereafter the wafer is rotated at high speed so as to have the applied water cut and be dried.
Further, a cleaning apparatus for cleaning a wafer by applying jet water or ultrasonic wave while rotating the wafer is known, as well as the above.
The above-described cleaning apparatuses, which clean a wafer while rotating it, have the disadvantage that the spin chuck contacts the major surface of the wafer. Moreover, since each of these apparatuses employs a large rotary mechanism for rotating the spin chuck at high speed, it needs a large space. In addition, cleaning water is transformed into a mist while watercut is performed by rotating a wafer at high speed, and the mist can disadvantageously be attached to the major surface of the wafer.